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Also referred to as an auger conveyor, the screw conveyor is a piece of equipment used to transport material between two points. The screw conveyor provides a high amount of efficiency by not needing any manual work to transport items.
Primarily, the conveyor involves a screw that rotates within a shaft and connected to a long trough. As rotation of the screw occurs, the material on the conveyor moves either forward or backward. The path of the conveyor can be inclined, horizontal, or vertical.
While the screw conveyor is available in a variety of types, its use will depend on what the purpose is and could involve moving animal feed, cement, fertilizer, and cereal.
From a historical standpoint, the Archimedes screw paved the way for the modern conveyor. With the Archimedes screw it played the role of a displacement pump that helped to remove water and carry it to ditches that were elevated for irrigation purposes.
The main part of the conveyor is the conveyor screw, which moves the material along its path. It is made up of a blade within a shaft and extends the entire length of the conveyor.
The screw works exactly like a screw should, making the material move each time a pitch is achieved and a full revolution is made. The screw’s pitch is the distance from one flight crest to another. The conveyor screw does not move while rotating and the material is moved along.
Common Screw Types
Standard Pitch Screw
With the conveyor having a standard pitch screw, the diameter is the same between the screw and pitch. The diameter of the screw is also the distance between both flight crests. The standard is used within a conveyor that is inclined and horizontal. The conveyor using this standard pitch screw is capable of handling a variety of materials.
Variable Pitch Screw
In this conveyor, there is an increase in pitch among the flight. There is a longer pitch that allows for more space for the material to exit as it comes out of a silo, hopper, or bins. The variable pitch is also incorporated into a screw feeder so that the rate of movement can be controlled.
Short Pitch Screw
With this short pitch, the screw’s diameter is two-thirds equal to the screw’s pitch.You will find these in a conveyor that is vertical and inclined. It also helps maintain a free-flowing transport system so no flushing will be needed.
When the conveyor has a half-pitch, the diameter of the screw is an equal half of its pitch. These conveyors are seen often in conveyors that are vertical and inclined.
Long Pitch Screw
This conveyor is long due to its screw diameter being long. This type of conveyor will be seen moving materials that are free-flowing or liquid. If material needs agitation, then this conveyor will be able to assist with that.